Turbine or compressor stator ring



June 2, 1953" J. B. wHEATLEY ET AL 2,640,579

TURBINE OR `COMPRESSOR STATOR RING Filed March-.21, 1950' 2 Sheets-Sheetl June 2, 1953 J. B. wHEATLEY ETAL TURBINE OR lCMPRESSOR STATOR RING 2Sheets-Sheet `2 Filed March 21, 1950 Patented June 2, 1953 UNITED STATESPATENT OFFICE TURBINE OR COMPRESSOR STATOR RING John B. Wheatley, ArthurW. Gaubatz, and

Charles C. Anderson, Indianapolis, Ind., assignors to General MotorsCorporation, Detroit, Mich., a corporation of Delaware Application March21, 1950, Serial No. 150,954

4 Claims. l

This invention relates to multistage rotary machines and particularly toan improved stator ring and seal structure for axial flow elastic fluidcompressors or turbines.

The: present invention is shown as being embodied in the stator ringstructure of the compressor of such a turbine and comprises an outerring or band which radially spaces the stator blades, an inner sealingmeans of one or more annular channels, and stator blades positionedbetween and secured to the outer band and the inner sealing channels.The bases of the outer band and the sealing channels are apertured toreceive projections or tenons formed on the ends of the stator blades,which blades are secured to the outer band and sealing channels byheading the blade tenons. This outer band is seated in an annular slotor groove formed in the inner surface of the compressor casing.

The principal object of the invention is to provide a stator ringstructure which is simple and inexpensive to manufacture and assemble,light in weight, and which possesses adequate structural strength. Thesefeatures, incorporated into the present invention, are particularlydesirable in aircraft turbine construction, where weight is such a.major consideration. The outer band and the sealing channels arepreferably constructed wholly of rolled stock, resulting in a ringstructure which possesses little weight and sufcient rigidity. Moreover,the entire ring structure may be constructed in two semi-circularsegments which are secured, one at a time, to the turbine compressorcasing, thereby facilitating assembly of the ring.

Another object of the invention is to provide an improved constructionand arrangement whereby loss due to leakage of elastic fluid around theblade tips is reduced to a minimum. This is accomplished in accordancewith the invention by the aforementioned sealing means comprising one ormore annular channels having apertured bases to which the stator bladetenons are afxed. The channel anges are adapted to project intoproximity with portions of the rotor discs, thereby constituting a veryeiective labyrinthine seal as Well as a structural support and spacingdevice for the stator blades.

Other objects and advantages of the invention will more fully appearfrom the following description taken inv conjunction with theaccompanying drawings in which:

Figure l is a fragmentary longitudinal section of a compressor of anaxial flow elastic fluid tur- 2 bine provided with blades and a statorring structure embodying the invention.

Figure 2 isk an enlarged sectional view, partly broken away, taken alongthe line 3-3 of Figure 2, showing one of the stator blades with theouter band and Sealing channels -attached thereto.

Figure 3is an end view, taken along theline 3-3 of Figure 2, showing thesemi-circular construction of the stator ring structure.

Figure 4 is an enlarged fragmentary view, partly in elevation and partlyin section, of aportion of the stator ring structure, showing the methodof attachment of the blades to the outer band and the sealing channels.

Referring to the drawings, the compressor of an axial iio-w elasticfluid turbine having a casing Ill is shown in Figure 1. Within thecasing IIJ is a` rotor with a shaft l2 passing through rotor discs I4and IE containing rotor bladesy I8 and 20, respectively. A stator ringstructure is located o-n either side of each row of rotor blades, eachstator ring comprising a row of stator blades 22 secured between acircular outer band 24 and annular sealing channels 26 and 28. Duringoperation the elastic uid is directed by the noz- Zles formed by thestator blades to the passages defined between the adjacent rotor bladesand discharged from the latter to the nozzles formed by the next annularseries of stator blades.

Leakage of fluid around the stator blades is materially reduced by theprovision of the aforementioned sealing means secured to the inner tipsof the stator blades. This sealing means, in a preferred embodiment, assho-wn in the drawings, comprises the two concentrically arrangedannular channel members 26 and 28. The larger outer channel 26 has abase or shroud portion 30 which may project beyond the edge of thestator blades 22, as shown in Figures 1 and 2, and two inwardly directedsealing flanges 32 and 34. The smaller inner channel, also comprises abase portion 36 and two inwardly extending sealing flanges 38 and 40,the base 36 of this smaller channel havinga width less than the baseportion 3U of the larger outer channel 26 and seated thereupon. Theedges of the resultant series of axially spaced flanges 32, 34, 38 and40 are adapted to project into proximity with an axial extension 42 ofrotor disc I6, thereby-acting as a very effective labyrinthine seal. Theembodiment of the invention shown in the drawings is one where thesealing channels are adapted to cooperate with a conical projection ofthe rotor disc. These flanges can be of various lengths or shapes adapt-3 ed to t irregularly contoured or rounded sealing members or surfaceson the rotor. The exact construction of the sealing flanges will begoverned, of course, by the contour of such rotor members.

As shown in the drawings, the tip portions of the compressor statorblades 22 are shaped to provide outer and inner projections or tenons 44and 46, respectively. The details of construction of these blade tenonsand the method of attachment of the sealing channels 26 and 28 and theouter band 24, which will be subsequently described, are best sho-Wn inFigures 2 and 4. It can be seen that the larger annular sealing channel2E is preferably of greater thickness than the smaller inner sealingchannel 28, the former supplying most of the rigidity to the sealstructure. The smaller channel is principally a sealing device, althoughit too contributes to the structural strength o-f the stator ring andaids in the alignment of the stator blades. The inner tenon 4B of thestator blade 22 has a length slightly greater than the combinedthicknesses of the bases and 36 of the sealing channels v26 and 28 topermit the heading of the tenons by electric upsetting or other suitablemeans, thereby securing the sealing channels to the blades. Similarlythe length of the outer blade tenon 44 is sufliciently greater than thethickness of the outer band 24 `to allow the ready attachment of theblades to the outer band by heading the blade tenons.

The base v3i) of the larger outer sealing channel 26 and the base 36 ofthe smaller inner sealing channel 28 are provided throughout theircircumferences with apertures 48 and 50, respectively, which are alignedto permit the inner tenons 4S of the stator blades 22 to be positionedin these apertures of both sealing channels, the same blade tensionsbeing used to secure both these members to the blade tips. As previouslystated. the blade tenons 48 are upset by appropriate means, theresultant tenen heads 52 being best shown Figure 4. Thus both sealingchannels 26 and 2e are securely fastened tothe same blade tenons in asingle operation without the necessity for any additional connectingmeans.

The outer band 24 extends laround the inside of and :engages the casing.This band, which functions principally to secure and radially space thestator blades, has `a base 54 provided with 'apertures 56 throughout.its circumference, with the outer tenons -44 of the stator bladespositioned in these Aapertures and headed, as hereinbefor'e described,to secure the .blades to the vother band. As shown in the drawings, theouter :band 2d may be formed with outwardly projecting peripheralflanges or rims 58 and 5U, which are vseated in an annular slot orgroove 52 formed in the inner surface Aof the casing. 'These rims '58and 6B, engaging the fcasing `groove $2, prevent vaxialmovement of thering structure and Aaid in the blade alignment, as well as increase thestructural strength of the stator ring. Moreover, as can be seen inFigures ,1 and 2, -th-is arrangement :provides an annular clearancespace between the base 54 of the outer stator band `24 and the casinglil .for the formed blade tenon heads 64.

The vouter band 24 and the sealing channels 26 vand 28 are eachpreferably constructed of rolled lstock and formed in two semi-circularsegments, as shown 'in vFigure 13, to facilitate assembly of the statorring. These ring members.

are sufficiently flexible so that after the inner blade tenons 46 arepositioned within the apertures 48 and 5G in the sealing channels 26 and28, and before any of the tenons are headed, these channels may bestraightened out enough to permit the insertion of the outer bladetenons 44 into the apertures 56 of the outer band 24, which in turn maybe ysprung over the outer tenons. Adequate clearances may be providedbetween the apertures 48, 5G and 56 and the blade tenons 44 and 46 toexpedite this procedure. Keepers 5S, shown in Figure l, may be employedto retain the ring structure within the'casing during assembly.

It will be understood that the term compressor, as -used hereinbefore,is not intended as a limitation on the use of the invention and vthatthe described stator ring structure is adapted generally for use incompressors, turbines and similar rotary machines where it isnecessaryto have a stationary blade assembly adjacent to rotor blades todirect the iiow of elastic fluid.

We claim:

l. A blade assembly for a iiuid machine of the dynamic type comprising,in combination, an arcuate outer strip, at least one arcuate inner stripof channel vform with the flanges directed inwardly, and a plurality ofblades extending from the outer strip to the inner strip, the depth ofthe said arcuate strips in a radial direction being small relative tothe length of the blades from one strip to the other, the said stripswhen unassembled being light and flimsy Aand readily deflected in aradial ldirection relative to the arcs thereof, means yon each end ofeach .blade abutting -on each of said strips throughout subsubstantially the axial extent of said blades, the blades extendingradially with respect to the arcs of the strips from a common center andbeing rigidly secured to the said strips so that the strips and bladescooperate .to form a rigid lattice and stiffen the said strips.

2. A blade assembly as claimed in claim 1 in which the arcuate extent ofthe strips is substantially degrees.

`3. A blade assembly as claimed in claim 1 in which the blades havetenons at each end and theV abutment .means includes shoulders at thebases of the tenons, openings through the strips through which thetenons extend, the blade shoulders bearing against one face of thestrips, and the tenons .rigidly secured against the other face of thestrips.

4,-A stator assembly for a .fluid machine of the dynamic type,comprising, in combination, a .casing formed with a shallowcircumferential groove in the inner surface thereof andan arcuate bladeassembly mounted therein comprising an arcuate outer strip, at least onearcuate .inner str-ip of vchannel form with the flanges directedinwardly, and a plurality of blades extending from the outer strip tothe inner strip, the depth of the said arcuate strips in a radialdirection being small relative to the length of the blades from onestrip to the other, the said strips when unassembled being light andiiimsy and 'readily deflected in a radial direction relative to the arcsthereof, means on each end of each blade abutting one each of saidstrips throughout substantiall-y the axial extent jof said blades, theblades extending radially with 'respect to the arcs of the strips from acommon center and .being rigidly secured to the said vstrips so that thestrips 'and vblades cooperate to form a rigid lattice and stiffenthesaid strips; the said outer arcuate strip being disposed in the saidgroove with the inner surface of the strip substantially correspondingto the inner surface of the casing.

Number JOI-IN B. WHEATLEY. 15,154, ARTHUR W. GAUBATZ. 5 26,333 CHARLESC. ANDERSON. 24,657 371,118

References Cited in the le of this patent UNITED STATES PATENTS NameDate lo Dahlstrand May 30, 1944 Number FOREIGN PATENTS Country DateGreat Britain June 27, 1907 Great Britain May 5, 1910 Great Britain Jan.23, 1913 France Jan. 12, 1907

